14.3 round 2: print sizes round Foundation's way, the shortest decimal then halves to even

AGENTS.md

@@ -183,7 +183,7 @@ Platform adaptations, each forced by a missing Qt analog:
 - The Smear's 1.4.2–1.4.3 fixes (13.16, part one: `7164dd4`, `ad9ad7c`, `504129d`, and `095da2f`'s commit half): Liquify is Swift's new GPU stroke on the CPU, as the twin has no Metal: `WarpStroke` keeps the layer as it found it (`m_original`, a copy made in the constructor) and a source offset per pixel (`m_offsets`, two floats each, zero at first); each dab copies the offsets under it to `m_scratch`, reads them bilinearly from behind the brush's travel, less the travel times the weight, writes them back, and draws the pixel afresh from the untouched layer, bilinear, held to its edges, each byte rounded once: `warp_push` of `MetalWarp.swift`, float for float (bytes over 255, mixed, times 255). Swift allocates the two textures on the first push; the twin allocates them with the stroke, before any dab (nothing changes the copy between), so a failure is `ExportError(render)` where `beginWarp` catches it, where Swift's guard returns in silence; Smudge's carried colour, allocated at the first dab inside `beginWarp`, fails the same way, and a dab's scratch that finds no memory skips that dab with a warning on `omaphoto.rendering`, Swift's guard on its scratch texture (review 2: it ran outside any catch). The colour reads keep the shader's `size - 2` as they are: the offsets' read above needs two columns and rows of the dab's area (`ix`, `iy`), which a canvas a pixel wide or tall lacks, so no read leaves the image; the clamps first written here for such canvases were dead and are removed (review 2). Smudge is `ad9ad7c` in both of Swift's paths: dabs every 0.005 of the width (a pixel at least), each dab lays what it carries at weight × strength, and carries what it just left, nothing older. `BrushSettings.blurRadius` (5) is the Blur's own Radius: the sample's sigma follows the Radius (see part two for the merged formula). `BrushControls` shows Radius for the Blur mode alone, after Strength: a scrubbable label (a tenth a point, 0.5–50), a 100-point slider over 0.5–20 in hundredths (past 20 Qt rests it at its end, so Swift's `min(20, …)` is left out), and a 42-point `PickerField` with "px": a readable number applies on Return or leaving, clamped, a number that is not finite takes 5 (Swift's binding), other text goes back, arrows step one (Shift ten) from the session's value, clamped; it prints Swift's `fractionLength(0...1)`, never grouped. `BrushStroke::maxDiameter` is 2100, so `finishWarp`'s tip four wider than a 2000 brush is no longer refused; `finishWarp` appends a dab centre only every twentieth of the brush (the last always), as Swift's; the thinning is `WarpStroke::committedPoints`, so the test reads it directly (`aCommitKeepsATwentiethAndTheLastPoint`). Part two (`095da2f`'s Blur half, on 13.11's grid sampling, cc9bf95 merged into port-d): `BrushStroke::Clone` is 13.11's `(image, placed, inGrid)` plus `render`, a function that makes a part of `image` (Swift's `cloneRender`; Swift keeps it beside `clone`, the twin inside it, so one assignment sets both), and `clone` is private behind `clone()` and `setClone()`, which drops the pieces cut so far (Swift's two `didSet`s). `clonePixels(key, tile)` is Swift's `clonePiece`: the tile mapped into sample pixels through 13.11's chain (grid, `pixelToDocument` unless `inGrid`, then `placed` to the image's pixels, Swift's `scaleX` and `scaleY`), two pixels round, made whole outward (`toAlignedRect`, Swift's `integral`), held to the image; an empty part paints nothing on that tile (the fill is skipped, as Swift's `if let piece`); otherwise the piece is `render(part)` or a copy, cut once per tile key and kept in `m_clonePieces`, and the tile's sample is drawn from it through the same transform shifted by the piece's corner, so every path reads the pixels the whole image would give. A piece that cannot be allocated is `ExportError(render)`, thrown on the calling thread with `publish`'s other copies, where Swift's `cropping` returning nil paints nothing. `blurSample(stroke)` returns the sharp sample in the stroke's grid (13.11's `region`, `fit` and budget unchanged) with `render` blurring a part at `sigma × fit`, padded by the Gaussian's reach (`ceil(3σ)`) and cut back, clear past the sample for pixels (`QImage::copy` fills outside with zeros), its edges repeated for a mask (Swift's `clampedToExtent`), so a piece equals that part of the whole byte for byte (Swift allows one level). The Radius sigma is Swift's `min(min(50, max(0.5, blurRadius)) / perPixel, sidePixels / 2)`. Merge: port-c's direct `clone =` writes became `setClone` (`beginBrush`, `finishWarp`, `cloneSample`'s callers, the tests and `documentClone`), every `Clone` initialiser names `render` (GCC's `-Wmissing-field-initializers`), and port-c's Blur sample tests compare the sharp sample (`framed`) and its softening through `render` (`soft`), with each brush size's old sigma now set as the Radius. Equivalent mutants and untested paths for part two: a piece, a padded copy or a cut-back blur that cannot Line truncated
 - Inner effects keep a pixel's alpha (14.1, Swift 1.4.6: `e7e295e`, `9cb57db`, `f25effa`): `LayerEffectsKernel` follows v1.4.9's `effects_compose`: the colour overlay, then the inner glow, then the inner shadow move each pixel's colour toward theirs times its alpha (MSL's `mix`, `recolour`), the overlay by its opacity, the inner two by their strength (`effects_inside`: 1 − the softened or moved shape, no longer times the shape); then the pixels go over the shadow, the outer glow and an outside stroke, and an inside stroke goes on top. So a half-clear pixel takes a colour fully and stays half clear, and effects beneath are not tinted. Swift's CPU path (`overlaid`, `recolor`, the surface's inner glow) serves machines without Metal and stays dead here, as 9.6b's. The effects button's tooltip says "Add layer effect". Tests: `ColorOverlayTests` (Swift's three; the inner shadow and inner glow on half-clear pixels, a shadow beneath untinted), the shader replay in `LayerEffectsKernelTests`.
 - RAW rounding and Importing… (14.2, Swift 1.4.6: `6345432`, `196342c`, `6e6ca38`, `0907f51`): `kernels/DitherPixels.c/.h` gain `196342c`'s `hash_noise` and `dither_quantize16`, its block body moved into `quantize_band` with a context struct, as 13.17's bands. `RawImporter::develop` works the look at 16 bits (`lround(65535 × …)`, opaque) into a buffer it allocates first (`ExportError(render)` without memory), then rounds it to 8 bits through `dither_quantize16`, where Swift renders Core Image at 16 bits and does the same; Swift's half-float working format names Core Image's own and has no twin. The session's `rawImporting` and `endRawDevelop` are Swift's: Import keeps the request and sets `rawImporting` while an answer waits, Cancel or an answer nobody waits for ends at once, and `finishDecode` ends it once the frame lands or fails (Swift's `defer`), after the layer is in. `RawDevelopSheet::setImporting` shows Swift's plate (a 32-point busy bar over "Importing…" in `PlaceholderText`, padded 16, on the window colour at 85% rounded 10), hides the preview's spinner, rests the sliders, Reset, Cancel and Import, and filters its dialog's Close and Escape while importing (Swift's `interactiveDismissDisabled`). Tests read RAW tones as a mean over the frame, rounded, since the noise moves single pixels a level; Qt's area average truncates, so a fitted preview reads a level low (`theQueueKeepsThePreviewsDecodeUntilReleased`). Holding the global pool freezes painting (Qt's raster engine fills on it), so the sheet's tests read its state before the event loop runs the develop, or use a frame large enough to take a while. Tests: `RawDitherTests` (Swift's two on the kernel; the triangular noise's three in four kept, alpha never passed, a develop dithered and repeatable), `RawDevelopTests` (importing, cancelling, failing, an answer nobody waits for, the plate, the locked dialog, the spinner and Reset while importing).
-- New Canvas in units, at a DPI, on a background (14.3, Swift 1.4.6: `b0b4f01`, `ab9779a`, `a00d8b6`): `NewCanvasUnit` and `NewCanvasBackground` (in `NewCanvasSheet.h`, Swift's file) are enums with free functions for Swift's members (`rawValue`, `name`, `next`, `pixels`, `text`; `title`, `next`, `color`). `pixels` trims Foundation's `.whitespaces` (`trimmedWhitespaces`), reads a comma as the point and parses as Swift's `Double(text)` (the whole text through `strtod_l` in the C locale, a leading white space refused), takes a positive number, turns a print size into pixels at the DPI rounded half away from zero, and wants a whole count from 1 to 30,000; Swift's `isFinite` term is dead (infinity fails the range, NaN the whole number) and left out. `text` prints whole pixels, or a print size to two decimals with none trailing, through glibc's `snprintf` in the C locale, whose exact halves go to the even digit as Foundation's do (Qt's own formatting rounds them up: 2.125 inches is 2.12). The sheet starts in pixels at 72 DPI on a clear canvas each time (`a00d8b6`), and its three settings are Swift's `CyclePill`s, `QAbstractButton`s that paint their text in `PlaceholderText` at 12 pixels and, hovered, a capsule of the text colour at 10% (macOS's quaternary label): the background (Transparent, White, Black canvas), the unit (switching rewrites both fields in the new unit when both read, else leaves them) and the DPI (72 or 300; in a print unit its tooltip adds the pixels it makes). The fields' units follow the unit; the note shows only for a size that does not read, in the unit's words; presets and the clipboard's size are written in the unit. `createNewProject` and `createDocument` take the resolution (1 to 9,600, else 72) and the background; `firstLayer` makes a Background layer of that colour at full size with its thumbnail, or a blank Layer 1, and a background that cannot be allocated logs on `omaphoto.app` and falls back to the blank layer, Swift's `try?` (untested: only starvation reaches it). Tests: `NewCanvasUnitTests` (Swift's four; rounding, trimming, the DPI's ends, the thumbnail), `NewCanvasSheetTests` (the pills, the units, the DPI's tooltip, presets in units, Swift's number parsing).
+- New Canvas in units, at a DPI, on a background (14.3, Swift 1.4.6: `b0b4f01`, `ab9779a`, `a00d8b6`): `NewCanvasUnit` and `NewCanvasBackground` (in `NewCanvasSheet.h`, Swift's file) are enums with free functions for Swift's members (`rawValue`, `name`, `next`, `pixels`, `text`; `title`, `next`, `color`). `pixels` trims Foundation's `.whitespaces` (`trimmedWhitespaces`), reads a comma as the point and parses as Swift's `Double(text)` (the whole text through `strtod_l` in the C locale, a leading white space refused), takes a positive number, turns a print size into pixels at the DPI rounded half away from zero, and wants a whole count from 1 to 30,000; Swift's `isFinite` term is dead (infinity fails the range, NaN the whole number) and left out. `text` prints whole pixels, or a print size to two decimals with none trailing, rounded as Foundation's format style rounds: the shortest decimal that reads back as the double (`QLocale::FloatingPointShortest`), then halves to even on its digits (1.905 cm prints 1.9, 3.175 prints 3.18, where rounding the binary value gives 1.91 and 3.17); checked once against Swift 6.0.3 for 1 to 4,000 pixels in every unit at 72 and 300 DPI, all 24,000 alike. The sheet starts in pixels at 72 DPI on a clear canvas each time (`a00d8b6`), and its three settings are Swift's `CyclePill`s, `QAbstractButton`s that paint their text in `PlaceholderText` at 12 pixels and, hovered, a capsule of the text colour at 10% (macOS's quaternary label): the background (Transparent, White, Black canvas), the unit (switching rewrites both fields in the new unit when both read, else leaves them) and the DPI (72 or 300; in a print unit its tooltip adds the pixels it makes). The fields' units follow the unit; the note shows only for a size that does not read, in the unit's words; presets and the clipboard's size are written in the unit. `createNewProject` and `createDocument` take the resolution (1 to 9,600, else 72) and the background; `firstLayer` makes a Background layer of that colour at full size with its thumbnail, or a blank Layer 1, and a background that cannot be allocated logs on `omaphoto.app` and falls back to the blank layer, Swift's `try?` (untested: only starvation reaches it). Tests: `NewCanvasUnitTests` (Swift's four; rounding, trimming, the DPI's ends, the thumbnail), `NewCanvasSheetTests` (the pills, the units, the DPI's tooltip, presets in units, Swift's number parsing).
 - Drops between projects: `ProjectWorkspace::draggedLayerSource` finds the tab whose document holds the dragged id (Swift reads the drag pasteboard; the twin reads the drag's `QMimeData`, which every drop target has), `canReceiveDrag(data, destination)` refuses only a layer's own tab, and `receiveProviders` copies several ids one after another, as Swift awaits each provider, so a two-row drop on the New button opens two tabs as Swift's does. `ContentView` takes such a drop over its whole area (`setWorkspace` hands it the workspace; `acceptsDrop` keeps Swift's guards: busy, the sheet, the importer, a rename; `levels` arrives with 9.x), shows the 3-point accent ring inside the canvas while targeted and hands the drop's document point on when it fell on the canvas. `ProjectTabButton` takes drops for its tab (accent fill and rim, "Add to <title>"), and `NewCanvasButton`, the toolbar's New canvas button with the action as its default, for a fresh tab ("Open in a new project tab"), both refusing an Alt drag, which duplicates in the panel; Swift's transient `NewTabDropSlot` in the strip has no twin, the New canvas button is `NewProjectDropTarget` already. Files and pictures arrived with 10.4.
 - `CanvasThumbnail` draws a layer or a mask inside the canvas's box at `backingScale` 2 (the panel's pixmaps carry that ratio); a mask's ground is `LayerMask::background`, white or black by its edge's majority, as the canvas treats it (Swift's `edgeTone` mean went with 12.12b). `LayerIcons` draws the panel's SF Symbols as paths, in one palette colour, like `ToolIcons`. `BlendModePicker` is a `QComboBox` whose popup previews the highlighted mode through `previewBlendMode` for the layer it opened on (Qt calls `hidePopup` before `activated`, so the preview, the target and the highlight are cleared from the event loop, after a choice had its chance) and refuses a choice once another layer is active. `LayerAppearanceControls` is Swift's blend and opacity row: the slider's press and release are one opacity drag (the release is watched application-wide while the slider is down, so a popup opened mid-drag cannot keep the step open), the percent field applies once through its `FocusOut`, which Return and Escape cause (Swift's `releasesFocusOnCommit`), and steps with Up and Down (Swift's `isFinite` test and the steps' clamp are left out: `setLayerOpacity` refuses a value that is no finite number and clamps the rest), and another active layer makes the controls anew, as Swift's `.id` does.
 - `ProjectWorkspaceView` is the `QMainWindow`: the front tab's `ContentView` as its central widget, made anew when another tab comes to the front, as SwiftUI's `.id` rebuilds it, and disabled while the workspace manages; the window holds the shown tab (`std::shared_ptr`) until the old editor is deleted, as Swift's views hold their session, so a replaced or closed tab's session never ends under its editor (`ProjectWorkspace::tab` is public for this); a `QToolBar` with the New canvas action, the `ProjectTabStrip` (which takes the toolbar's free width) and the four zoom actions, since SwiftUI's `.toolbar` modifier lives in `ContentView` but the toolbar belongs to the window. Its actions follow the front session's `changed()`, and on that signal the window syncs every tab's button as well, because a busy front tab dims the other tabs' buttons, which their own sessions' signals do not reach; the strip syncs its buttons on the workspace's signal, each button on its own session's. The window's title is the front tab's, with Qt's `[*]` placeholder, so `setWindowModified` can show the mark that `isDocumentEdited` shows; `setWindowFilePath` carries `representedURL`. The editor's own minimum size is cleared inside the window, which owns the 800 × 520 minimum for the whole, toolbar included. Closing the window ignores the event and asks the workspace (`closeWindow`), which confirms tab by tab and then closes the window again with the property `closeConfirmed` set, since the workspace may not include `UI/` headers; a confirmed close is accepted and the mark cleared, so a window shown again asks again. `ProjectTabStrip` is a plain `QWidget` whose buttons are kept for the tabs that stay, made for new tabs and deleted for tabs that went, and placed by hand from `projectTabOverflow` (13.14): every button at its own size hint, so no title is squeezed below Swift's 35 points, laid out again when the strip is resized, the workspace changes or any tab's session changes; it fills no background, so the toolbar shows through (a stylesheet would do the same but freezes the widgets' palette, so a theme switch would pass them by); the unsaved dot is a character before the title. Files named on the command line go to `ProjectWorkspace::receive`, as Finder's Open With reaches the delegate. Layer drops on tabs and the New canvas button are 4.7's; file and picture drops arrived with 10.4.

src/UI/NewCanvasSheet.cpp

@@ -9,13 +9,13 @@
 #include <QImageReader>
 #include <QMenu>
 #include <QPainter>
+#include <QRegularExpression>
 #include <QShortcut>
 #include <QVBoxLayout>
 #include <algorithm>
 #include <cctype>
 #include <clocale>
 #include <cmath>
-#include <cstdio>
 #include <cstdlib>
 
 namespace {
@@ -151,17 +151,20 @@ QString text(NewCanvasUnit unit, int pixels, double resolution)
     const std::optional<double> inch = perInch(unit);
     if (!inch)
         return QString::number(pixels);
-    // glibc's halves go to even, as Foundation's; Qt's do not.
-    static const locale_t c = newlocale(LC_ALL_MASK, "C", locale_t(nullptr));
-    const locale_t previous = uselocale(c);
-    char digits[64];
-    std::snprintf(digits, sizeof digits, "%.2f", double(pixels) / resolution * *inch);
-    uselocale(previous);
-    QString written = QString::fromLatin1(digits);
-    while (written.endsWith(u'0'))
-        written.chop(1);
-    if (written.endsWith(u'.'))
-        written.chop(1);
+    // Foundation rounds the shortest decimal, halves to even.
+    const QString shortest = QString::number(double(pixels) / resolution * *inch, 'f', QLocale::FloatingPointShortest);
+    const qsizetype point = shortest.indexOf(u'.');
+    const QString fraction = point < 0 ? QString() : shortest.mid(point + 1);
+    qint64 hundredths = shortest.left(point < 0 ? shortest.size() : point).toLongLong() * 100 + fraction.left(2).leftJustified(2, u'0').toLongLong();
+    if (fraction.size() > 2) {
+        const QChar next = fraction[2];
+        const bool beyond = fraction.mid(3).contains(QRegularExpression(QStringLiteral("[1-9]")));
+        if (next > u'5' || (next == u'5' && (beyond || hundredths % 2 == 1)))
+            hundredths += 1;
+    }
+    QString written = QString::number(hundredths / 100);
+    if (const qint64 cents = hundredths % 100; cents != 0)
+        written += u'.' + (cents % 10 == 0 ? QString::number(cents / 10) : QString::number(cents).rightJustified(2, u'0'));
     return written;
 }
 

tests/NewCanvasUnitTests.cpp

@@ -1,5 +1,6 @@
 #include "UI/NewCanvasSheet.h"
 #include <QtTest>
+#include <tuple>
 
 // Swift's NewCanvasUnitTests: units, DPI and the first layer.
 class NewCanvasUnitTests : public QObject {
@@ -45,10 +46,18 @@ void NewCanvasUnitTests::unitsRoundTripAndCycle()
     QCOMPARE(text(NewCanvasUnit::inches, 3000, 300), QString("10"));
     QCOMPARE(text(NewCanvasUnit::millimeters, 2480, 300), QString("209.97"));
     QCOMPARE(text(NewCanvasUnit::centimeters, 30000, 72), QString("1058.33"));
-    // Exact halves go to the even digit, as Foundation rounds.
-    QCOMPARE(text(NewCanvasUnit::inches, 153, 72), QString("2.12"));
-    QCOMPARE(text(NewCanvasUnit::inches, 9, 72), QString("0.12"));
-    QCOMPARE(text(NewCanvasUnit::inches, 27, 72), QString("0.38"));
+    // Foundation rounds the shortest decimal, halves to even (Swift 6.0.3).
+    const std::vector<std::tuple<NewCanvasUnit, int, double, QString>> halves{
+        {NewCanvasUnit::inches, 153, 72, "2.12"}, {NewCanvasUnit::inches, 9, 72, "0.12"}, {NewCanvasUnit::inches, 27, 72, "0.38"},
+        {NewCanvasUnit::centimeters, 54, 72, "1.9"}, {NewCanvasUnit::centimeters, 90, 72, "3.18"}, {NewCanvasUnit::centimeters, 126, 72, "4.44"},
+        {NewCanvasUnit::centimeters, 3006, 72, "106.04"}, {NewCanvasUnit::centimeters, 3042, 72, "107.32"}, {NewCanvasUnit::centimeters, 3186, 72, "112.4"},
+        {NewCanvasUnit::millimeters, 9, 72, "3.18"}, {NewCanvasUnit::millimeters, 3789, 72, "1336.68"}, {NewCanvasUnit::millimeters, 3969, 72, "1400.18"},
+        {NewCanvasUnit::inches, 3, 300, "0.01"}, {NewCanvasUnit::millimeters, 30000, 300, "2540"}, {NewCanvasUnit::inches, 22, 72, "0.31"},
+        {NewCanvasUnit::inches, 166, 72, "2.31"}};
+    for (const auto &[unit, count, dpi, written] : halves)
+        QCOMPARE(text(unit, count, dpi), written);
+    // Foundation: the shortest decimal, halves to even (Swift 6.0.3).
+    QCOMPARE(pixels(NewCanvasUnit::centimeters, text(NewCanvasUnit::centimeters, 54, 72), 300), std::optional(224));
     QCOMPARE(text(NewCanvasUnit::pixels, 30000, 72), QString("30000"));
     for (NewCanvasUnit unit : {NewCanvasUnit::inches, NewCanvasUnit::centimeters, NewCanvasUnit::millimeters})
         QCOMPARE(pixels(unit, text(unit, 2550, 300), 300), std::optional(2550));